1. Field of the Invention
This invention relates to a wafer cleaning apparatus in a manufacturing stage for a semiconductor device, and more particularly a technology for removing particles left on the wafer surface within a vacuum environment after processing or after flattening at a pre-stage of the semiconductor manufacturing process.
2. Description of the Related Prior Art
In the prior art cleaning for a semiconductor wafer (hereinafter abbreviated as a wafer), the cleaning operation is carried out such that either pure water or a solution diluted with various kinds of acids or an alkaline solution is applied. The wafer is immersed in the solution or the solution is blown against the wafer to wash away particles at the surface of the wafer. In addition, a method for mechanically cleaning the wafer surface with a brush concurrently with immersion of the wafer in the solution or the like is also used.
The aforesaid cleaning method of the prior art shows the following problems due to the fact that this is a so-called wet cleaning method in which basically water is used for cleaning operation.
1) Although a continuous total processing within a vacuum environment such as a dry etching or a plasma CVD or the like increases a machining precision or manufacturing efficiency, cleaning operation required after each of the processings is a wet type processing, so that it generates a necessity for once putting out the wafer into atmosphere and thus the aforesaid effects may not be attained.
2) The wet cleaning operation requires a rinsing stage and a drying stage in addition to the cleaning operation, resulting in that the number of manufacturing stages is increased.
3) In the case of wet cleaning operation, the local surface of the semiconductor material is degraded in its quality and as the size of a semiconductor is made fine, its yield is reduced by the degraded material quality at the surface.
4) In the case of performing the wet cleaning operation, liquid is not sufficiently immersed on small structural parts sometimes due to a surface tension of liquid and cleaning power with respect to the small structural part is insufficient.
5) A high performance device has required high wet-absorbing material such as organic film or porous organic film as a new material for a semiconductor device, and, in particular, an insulating film material as a new material in the future. In the case of manufacturing the semiconductor device using these new materials, either the wet cleaning or a mere occasional exposure in the surrounding atmosphere causes a characteristic of the device to be deteriorated.
6) A wet cleaning is normally carried out under a batch processing. In the case that the wafer has 300 mm xcfx86 (diameter) or more, it takes much time in cleaning of the wafer and handling before and after the cleaning.
In turn, as a cleaning method in place of the aforesaid wet cleaning operation, there is provided a dry cleaning method. As to the dry cleaning method, this method has been disclosed in Japanese Patent Laid-Open Nos. Hei 8-131981, 8-85887 or 9-17776, for example.
It is an object of the present invention to provide a dry cleaning device capable of attaining a cleaning power corresponding to the wet processing even in cleaning within a vacuum environment in order to solve the problems accompanied with the aforesaid wet cleaning.
A summary of the disclosed invention that is a representative one of the disclosed inventions will be described in brief as follows.
The present invention is characterized in that the particles left at the surface of the wafer are physically removed with a high-speed gas flow by a method wherein a pad or block is moved near the surface of the wafer, gas is injected into a clearance or space between the pad and the surface of the wafer and a high speed gas flow along the surface of the wafer is generated.